U.S. patent number 5,733,802 [Application Number 08/538,204] was granted by the patent office on 1998-03-31 for semiconductor device and method of manufacturing the same.
This patent grant is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Yumi Inoue, Tsutomu Nakazawa.
United States Patent |
5,733,802 |
Inoue , et al. |
March 31, 1998 |
**Please see images for:
( Certificate of Correction ) ** |
Semiconductor device and method of manufacturing the same
Abstract
There is provided a semiconductor device having a very thin,
highly reliable semiconductor package and a method of easily
manufacturing the semiconductor apparatus. The method comprises a
first step of coating and melting a thermosetting resin in a mold
for resin sealing, while keeping the mold at a predetermined
temperature, the mold being divided into an upper mold and a lower
mold, a second step of fixing within the mold a lead frame
supporting a semiconductor chip, and a third step of applying a
pressure on the mold and compression-molding the resin, thus
forming a package.
Inventors: |
Inoue; Yumi (Yokohama,
JP), Nakazawa; Tsutomu (Yokohama, JP) |
Assignee: |
Kabushiki Kaisha Toshiba
(Kawasaki, JP)
|
Family
ID: |
17097286 |
Appl.
No.: |
08/538,204 |
Filed: |
October 3, 1995 |
Foreign Application Priority Data
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Oct 6, 1994 [JP] |
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6-242992 |
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Current U.S.
Class: |
438/127;
257/E21.504; 438/112; 438/124; 438/126 |
Current CPC
Class: |
H01L
21/565 (20130101); H01L 2224/48091 (20130101); H01L
2224/48247 (20130101); H01L 2224/49171 (20130101); H01L
2924/14 (20130101); H01L 2224/48091 (20130101); H01L
2924/00014 (20130101); H01L 2224/49171 (20130101); H01L
2224/48247 (20130101); H01L 2924/00 (20130101) |
Current International
Class: |
H01L
21/02 (20060101); H01L 21/56 (20060101); H01L
021/60 () |
Field of
Search: |
;437/209,211,213,214,215,217,218,219,220
;438/111,112,118,119,121,124,125,126,127 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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5-90314 |
|
Apr 1993 |
|
JP |
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5-175264 |
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Jul 1993 |
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JP |
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Primary Examiner: Picardat; Kevin
Attorney, Agent or Firm: Finnegan, Henderson, Farabow,
Garrett & Dunner, L.L.P.
Claims
What is claimed is:
1. A method of manufacturing a semiconductor device,
comprising:
a first step of coating and melting a thermosetting resin in an
inside surface of an upper mold and a lower mold for resin sealing,
while keeping the mold at a [predetermined]temperature;
a second step of fixing within said upper and lower molds one of a
lead frame and a TAB tape supporting a semiconductor chip; and
a third step of applying a pressure on the upper and lower molds
and compression-molding the resin, thus forming a package.
2. The method of manufacturing the semiconductor device according
to claim 1, wherein a powder resin is sprayed to coat the resin on
the inside of the upper and lower molds in said first step.
3. The method of manufacturing the semiconductor device according
to claim 2, wherein when said powder resin is sprayed, said powder
resin is simultaneously supplied onto the insides of said upper and
lower molds from a single nozzle having upwardly and downwardly
branched distal end portions.
4. The method of manufacturing the semiconductor device according
to claim 2, wherein when said powder resin is sprayed, said powder
resin is supplied separately onto the insides of said upper and
lower molds from two nozzles.
5. The method of manufacturing the semiconductor device according
to claim 2, wherein when said powder resin is sprayed, said powder
resin is supplied onto the inside of the mold from a nozzle having
a plurality of opening distal end portions.
6. The method of manufacturing the semiconductor device according
to claim 3, wherein when said powder resin is sprayed, said powder
resin is supplied onto the inside of the mold while the nozzle is
being moved.
7. The method of manufacturing the semiconductor device according
to claim 4, wherein when said powder resin is sprayed, said powder
resin is supplied onto the inside of the mold while the nozzle is
being moved.
8. The method of manufacturing the semiconductor device according
to claim 5, wherein when said powder resin is sprayed, said powder
resin is supplied onto the inside of the mold while the nozzle is
being moved.
9. The method of manufacturing the semiconductor device according
to claim 2, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
10. The method of manufacturing the semiconductor device according
to claim 3, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
11. The method of manufacturing the semiconductor device according
to claim 4, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
12. The method of manufacturing the semiconductor device according
to claim 5, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
13. The method of manufacturing the semiconductor device according
to claim 6, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
14. The method of manufacturing the semiconductor device according
to claim 7, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
15. The method of manufacturing the semiconductor device according
to claim 8, wherein when said powder resin is sprayed, an equal
amount of resin is supplied onto the insides of the upper and lower
molds.
16. The method of manufacturing the semiconductor device according
to claim 2, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
17. The method of manufacturing the semiconductor device according
to claim 3, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
18. The method of manufacturing the semiconductor device according
to claim 4, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
19. The method of manufacturing the semiconductor device according
to claim 5, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
20. The method of manufacturing the semiconductor device according
to claim 6, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
21. The method of manufacturing the semiconductor device according
to claim 7, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
22. The method of manufacturing the semiconductor device according
to claim 8, wherein when said powder resin is sprayed, different
amounts of resin are supplied onto the insides of the upper and
lower molds.
23. The method of manufacturing the semiconductor device according
to claim 1, wherein in order to coat the resin onto the inside of
the mold in said first step, a resin formed by powdering a resin
table for transfer molding is sprayed.
24. The method of manufacturing the semiconductor device according
to claim 1, wherein a liquid resin is coated onto the inside of the
mold in said first step.
25. The method of manufacturing the semiconductor device according
to claim 2, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
26. The method of manufacturing the semiconductor device according
to claim 3, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
27. The method of manufacturing the semiconductor device according
to claim 4, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
28. The method of manufacturing the semiconductor device according
to claim 5, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
29. The method of manufacturing the semiconductor device according
to claim 6, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
30. The method of manufacturing the semiconductor device according
to claim 7, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
31. The method of manufacturing the semiconductor device according
to claim 8, wherein when said powder resin is sprayed, different
kinds of resins are supplied onto the insides of the upper and
lower molds.
32. The method of claim 1, wherein the first step is completed
prior to beginning the third step.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device and a
method of manufacturing the same and more particularly to a
semiconductor device having a resin-sealed package and a method of
manufacturing the same.
2. Description of the Related Art
FIGS. 18A to 18C show examples of resin-sealed packages of
conventional semiconductor devices, manufactured by using TAB (Tape
Automated Bonding) techniques. Reference numeral 81 denotes a
semiconductor chip, 82 a bump electrode formed on the semiconductor
chip 81, 83 a TAB lead, 84 a polyimide tape for supporting the TAB
lead 83, and 85 a protection resin sealing the semiconductor chip
81 and inner lead portions of the lead 83.
In the package shown in FIG. 18A, a solid resin sheet formed by
glass fibers impregnated with epoxy resin is cut to a size slightly
greater than the size of the chip 81, and the cut solid resin sheet
is attached to each side surface of the chip 81 and thermally
melted, thus forming-the protection resin 85. This structure was
widely used when the TAB technique began to prevail, but now it is
not widely used.
In the package shown in FIG. 18B, a solvent type liquid-phase resin
is coated by a potting method on the surfaces of the chip 81 as
well as the inner lead portions of the lead 83. The resin is then
solidified by several heat treatment processes, thereby forming the
protection resin 85. This structure is now prevalent since a
relatively thin package can be obtained.
In the package shown in FIG. 18C, the chip 81 on which the inner
lead portions have been bonded is sealed with resin, thereby
forming the protection resin 85. This package is formed by a
transfer mold method for resin-sealing a chip on a lead frame.
FIGS. 19A to 19F show examples of steps of resin-sealing a
conventional semiconductor device with a lead frame by a transfer
mold apparatus. Reference numeral 90 denotes a mold, 90a an upper
mold, 90b a lower mold, 90c a pot portion, 90d a cavity portion,
90e a cull portion, 90f a runner portion, and 90g a gate portion.
Numeral 91 denotes a semiconductor chip, 92 a lead frame, 94 a
resin tablet, 96 a plunger, and 97 a high frequency heater.
As is shown in FIG. 19A, the lead frame 92 supporting the chip 91
already subjected to the bonding process is set on the heated lower
mold 90b. The upper mold 90a is lowered and fixed. Then, as shown
in FIG. 19B, the resin tablet 94 is preheated by the high frequency
heater 97, and the preheated tablet 94 is inserted through the pot
portion 90c, as shown in FIG. 19C. Subsequently, the plunger 96 is
lowered, as shown in FIG. 19D, and the resin is injected into the
cavity portion 90d of the mold and solidified.
FIG. 20 illustrates the flow of the resin 90a in the transfer mold
apparatus in the step shown in FIG. 19D. After the resin tablet 94
is fed into the pot portion 90c, the tablet 94 is injected by the
plunger 96 and put into the cavity portion 90d as resin 94a via the
runner portion 90f and gate portion 90g. The lead frame 92 is set
in the cavity portion 90d, as mentioned above, and the chip 91 is
mounted on a die pad portion 92a of the lead frame 92. Electrodes
on the chip 91 are connected to the lead frame 92 by bonding wires
93.
After the upper mold 90a is raised and the molded product is taken
out, as shown in FIG. 19E, a resin-sealed package 98 is cut and
completed as a single body, as shown in FIG. 19F.
However, the semiconductor package shown in FIG. 18A does not have
a uniform outer shape, and thus it is difficult to reduce the
thickness thereof. Although the thickness of the semiconductor
package shown in FIG. 18B can be reduced, the bottom of the chip is
not resin-sealed. Consequently, thermal expansion is unbalanced,
and the lead may be cut or cracks may occur in the chip due to
thermal stress. Moreover, since this package is not subjected to
thermal pressure contact molding using a mold, etc., the outer
shape thereof is not regular. Besides, the transfer mold type
semiconductor package shown in FIGS. 18C and 19A to 19F can be
manufactured to have a uniform outer shape. However, it is
necessary to preheat the resin tablet 94 by the high frequency
heater 97 prior to the molding. In addition, when the resin 94a is
injected, the bonding wire 93 may be deformed, the die pad portion
92a of the lead frame 92 supporting the chip 91 may be inclined, or
the resin may not be fully injected, resulting in non-sealed
portions.
Furthermore, when the thickness of the package is extremely
reduced, the flow of the resin 94a in the cavity portion 90d is
considerably limited, resulting in incomplete filling of the resin
or occurrence of a void. Even a slight inclination of the chip 91
is also a serious problem.
As an example of a thinned package, suppose a memory card in which
a memory LSI chip is resin-sealed. In general, the memory card is
mounted in a multiple-stacked manner or in a very narrow space.
Thus, the outer shape of the package needs to be uniform.
Therefore, the package must be formed not by a bonding seal method
but by a mold method such as a transfer mold method, so as to have
a uniform outer shape.
However, when the thin package is formed by the transfer mold
method, as described above, a slight inclination of the chip during
the resin injection may result in a non-sealed portion of the chip.
It is difficult to stably form the thin package by the transfer
mold method. In the case where the thickness of the die pad portion
of the lead frame is about 150 .mu.m, the thickness of the LSI chip
is about 350 .mu.m and the thickness of a resin layer which can be
formed by the transfer mold method on the upper and lower surfaces
of the LSI chip is about 100 .mu.m, the thickness of the package
stably formed by the transfer mold method exceeds about 1 mm at
present.
As has been described above, the conventional semiconductor
apparatus has a problem in that it is difficult to stably form a
very thin package with a thickness of 1 mm or less by
injection-molding a resin by the transfer mold method.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above
problem, and its object is to provide a semiconductor device having
a very thin, highly reliable semiconductor package and a method of
easily manufacturing the semiconductor apparatus.
According to this invention, there is provided a semiconductor
device wherein a semiconductor chip is resin-sealed in a package
formed by resin compression with use of a mold so as to have a
thickness of 1 mm or less.
There is also provided a method of manufacturing a semiconductor
device, comprising:
a first step of coating and melting a thermosetting resin in a mold
for resin sealing, while keeping the mold at a predetermined
temperature, said mold being divided into an upper mold and a lower
mold;
a second step of fixing within said mold one of a lead frame and a
TAB tape supporting a semiconductor chip; and
a third step of applying a pressure on the mold and
compression-molding the resin, thus forming a package.
Additional objects and advantages of the invention will be set
forth in the description which follows, and in part will be obvious
from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute
a part of the specification, illustrate presently preferred
embodiments of the invention and, together with the general
description given above and the detailed description of the
preferred embodiments given below, serve to explain the principles
of the invention.
FIGS. 1A to 1D show examples of steps of forming a package of a
semiconductor device with use of a lead frame, according to a first
embodiment of the present invention;
FIGS. 2A and 2B show examples of steps of forming a package of a
semiconductor device with use of a lead frame, according to a
second embodiment of the present invention;
FIGS. 3A and 3B show examples of steps of forming a package of a
semiconductor device with use of a TAB method, according to a third
embodiment of the present invention;
FIG. 4 is a cross-sectional view showing a package of a
semiconductor device with use of a lead frame, according to a
fourth embodiment of the present invention;
FIG. 5 is a cross-sectional view showing a package of a
semiconductor device with use of a lead frame, according to a fifth
embodiment of the present invention;
FIG. 6 is a cross-sectional view showing a package of a
semiconductor device with use of a lead frame, according to a sixth
embodiment of the present invention;
FIG. 7 shows the state in which a powder resin is sprayed on the
mold from a nozzle used in an example of a step of coating a resin
on the mold in the method of manufacturing the semiconductor device
according to the present invention;
FIG. 8 shows the state in which a liquid resin is sprayed on the
mold from a nozzle used in another example of a step of coating a
resin on the mold in the method of manufacturing the semiconductor
device according to the present invention;
FIG. 9 is a side view showing an example of the shape of a nozzle
used in another example of a step of coating a resin on the mold in
the method of manufacturing the semiconductor device according to
the present invention;
FIG. 10 is a side view showing another example of the shape of a
nozzle used in another example of a step of coating a resin on the
mold in the method of manufacturing the semiconductor device
according to the present invention;
FIG. 11 is a side view showing an example of the shape of a distal
end portion of a nozzle used in a step of coating a resin on the
mold in the method of manufacturing the semiconductor device
according to the present invention;
FIGS. 12A and 12B are side views showing examples of driving
manners of nozzles used in a step of coating a resin on the mold in
the method of manufacturing the semiconductor device according to
the present invention;
FIG. 13 is a side view showing still another example of the shape
of a nozzle used in a step of coating a resin on the mold in the
method of manufacturing the semiconductor device according to the
present invention;
FIG. 14 is a side view showing still another example of the shape
of a nozzle used in a step of coating a resin on the mold in the
method of manufacturing the semiconductor device according to the
present invention;
FIG. 15 is a side view showing an example of a driving manner of
the nozzle shown in FIG. 13.
FIG. 16 is a side view showing an example of a driving manner of
the nozzle shown in FIG. 14;
FIGS. 17A and 17B are a plan view and a cross-sectional view
showing a semiconductor device with use of a lead frame, according
to a seventh embodiment of the present invention;
FIGS. 18A to 18C show examples of resin-sealed packages of
conventional semiconductor devices with use of TAB techniques;
FIGS. 19A to 19F show examples of steps of resin-sealing a package
of a conventional semiconductor device with use of a lead frame by
means of a transfer mold apparatus; and
FIG. 20 shows the flow of the resin in the transfer mold apparatus
in the steps shown in FIGS. 19A to 19F.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will now be described in
detail with reference to the accompanying drawings. FIGS. 1A to 1D
show examples of steps of forming a package of a semiconductor
device with use of a lead frame, according to a first embodiment of
the present invention. Reference numeral 10 denotes a mold for
resin sealing which includes an upper mold 10a, a lower mold 10b
and a cavity portion 10c. Numeral 11 denotes a semiconductor chip,
and 12 a lead frame. The semiconductor chip 11 is attached on a die
pad portion 12a of the lead frame 12 by means of an adhesive (not
shown). Numeral 13 denotes bonding wires for electrically
connecting electrodes (not shown) of the semiconductor chip 11 to
the lead frame 12. Numeral 14 denotes a thermosetting resin, and 15
a resin package formed by compression-molding the resin 14 so as to
seal the chip 11, bonding wires 13 and inner lead portions of the
lead frame 12.
When the package is formed, the semiconductor chip 11 is attached
and mounted on the die pad portion 12a in advance, and the
electrodes of the chip 11 are connected to the lead frame 12 by the
bonding wires 13. On the other hand, as shown in FIG. 1A, the mold
10 comprising the upper mold 10a and lower mold 10b is kept at a
predetermined temperature (e.g. about 100.degree. C. to 170.degree.
C.). The thermosetting resin 14 is coated on the inside surfaces of
the mold 10 and melted. In this example, a powder resin is sprayed
on the inside surfaces of the mold (i.e. on the walls defining the
cavity portion 10c). In this case, the molten resin 14 on the upper
mold 10a remains in the upper mold 10a by virtue of the viscosity
and surface tension of the resin 14. However, when a thick package
is formed, the amount of resin sprayed on the upper mold 10a
increases and the resin in the upper mold 10a may drop. In order to
prevent the dropping of the resin, the physical properties and mold
temperature must be optimally determined when the amount of resin
is large.
As is shown in FIG. 1B, the lead frame supporting the chip is fixed
in the mold 10 (i.e. between the upper mold 10a and lower mold 10b
in this example). A vertical pressure is applied to the mold 10 and
the molten resin 14 is compression-molded. After the resin is
solidified to some extent, the upper and lower molds 10a and 10b
are separated and the lead frame 12 is taken out of the mold 10, as
shown in FIG. 1C. Subsequently, as shown in FIG. 1D, outer lead
portions 12b of the lead frame 12, which are located outside the
resin structure, are processed to have a shape suitable for
mounting on a circuit board (not shown) (in this example, a
gull-wing shape). Thus, the resin-sealed package 15 is formed.
According to the manufacturing steps of the first embodiment, the
outer shape of the package can be made uniform, like a package
formed by a conventional transfer mold method.
In addition, unlike the transfer mold method, the flow of the resin
is not required. Thus, it is possible to prevent floating,
inclination or exposure of the chip in the resin-sealed package. A
thin resin-sealed package can be advantageously realized. For
example, in the case where a thin resin-sealed package is formed by
a conventional molding method such as a transfer mold method which
requires the flow of resin, if the amount of supplied resin is
small, the resin is not filled in the entire inner space of the
mold. As a result, a thin package is not obtained. According to the
present embodiment, however, the amount of resin supplied into the
mold can be reduced and the thin package can be easily formed.
Furthermore, in the transfer mold method, a resin must be wasted in
the cull portion, runner portion, etc. in order to flow the resin.
In the present embodiment, no resin is wasted and the amount of
necessary resin can be remarkably reduced.
According to the manufacturing steps of this embodiment, the resin
need not be preheated at the time of resin-sealing. Since the mold
is kept at high temperatures (e.g. 100.degree. C. to 170.degree.
C.) and the powder resin (i.e. a resin in the easily meltable
state) is coated on the mold, the resin can be easily melted and
the manufacturing time can be remarkably reduced.
FIGS. 2A and 2B show examples of steps of forming a package of a
semiconductor device with use of a lead frame, according to a
second embodiment of the present invention. A mold 10 for resin
sealing includes an upper mold 10a, a lower mold 10b and a cavity
portion 10c. Numeral 11 denotes a semiconductor chip, and 12 a lead
frame. The lead frame 12 does not have a die pad portion but has a
chip mount hole. Numeral 13 denotes bonding wires for electrically
connecting electrodes of the semiconductor chip 11 to the lead
frame 12. The semiconductor chip 11 is not fixed at its upper
surface or its lower surface. The chip 11 is mounted in the chip
mount hole in the lead frame 12. The chip 11 is fixed to the lead
frame 12 on its sides by means of an adhesive 16. Numeral 14
denotes a thermosetting resin, and 15 a resin package formed by
compression-molding the resin 14 so as to seal the chip 11, bonding
wires 13 and inner lead portions of the lead frame 12.
When the package is formed, the side faces of the lead frame 12 are
bonded to the side surfaces of the chip 11 by the adhesive 16 in
advance and the electrodes of the chip 11 are connected to the lead
frame 12 by the bonding wires 13. The mold 10 is kept at a
predetermined temperature (e.g. 100.degree. C. to 170.degree. C.).
The thermosetting resin 14 is coated on the inside surfaces of the
upper and lower molds 10a and 10b and melted.
In this state, the lead frame 12 supporting the chip, as mentioned
above, is fixed between the upper mold 10a and lower mold 10b. A
pressure is applied to the mold 10 and the resin 14 is
compression-molded. After the resin 14 is solidified to some
extent, the lead frame 12 is taken out of the mold 10.
Subsequently, as shown in FIG. 2B, outer lead portions 12b of the
lead frame 12, which are located outside the resin structure, are
processed to have a shape suitable for mounting on a circuit board.
Thus, a resin-sealed package 15, which is thinner than the package
of the first embodiment at least by a degree corresponding to the
thickness of the die pad portion (12a in FIG. 1) of the lead frame,
is formed.
FIGS. 3A and 3B show examples of steps of forming a package of a
semiconductor device with use of a TAB method, according to a third
embodiment of the present invention. A mold for resin sealing
includes an upper mold 10a, a lower mold 10b and a cavity portion
10c. Numeral 21 denotes a semiconductor chip on which bump
electrodes 21a are formed. Numeral 22 denotes a TAB lead supported
on a polyimide tape 23. The bump electrodes 21a of the
semiconductor chip 21 are bonded and fixed to the TAB lead 22.
Numeral 14 denotes a thermosetting resin, and 15 a resin package
formed by compression-molding the resin 14 so as to seal the chip
21 and inner lead portions of the TAB lead 22.
When the package is formed, the TAB lead 22 is bonded to the bump
electrodes 21a of the chip 21. The mold is kept at a predetermined
temperature (100.degree. C. or above in this embodiment). The
thermosetting resin 14 is coated on the inside surfaces of the
upper and lower molds 10a and 10b and melted.
In this state, the TAB tape 23 supporting the chip, as mentioned
above, is fixed between the upper and lower molds. A pressure is
applied to the mold and the resin 14 is compression-molded. After
the resin 14 is solidified to some extent, the TAB lead 22 is taken
out of the mold. Subsequently, as shown in FIG. 3B, outer lead
portions 22b of the TAB lead 22, which are located outside the
resin structure, are processed to have a shape suitable for
mounting on a circuit board. Thus, a resin-sealed package 15 is
formed.
The method of fixing the side surfaces of the chip by using a lead
frame having no die pad portion is not limited to the method of the
second embodiment in which the adhesive is used. A method of fixing
by making use of elastic deformation (spring effect) of a lead
frame or a method of plastically deforming a lead frame may be
adopted.
FIG. 4 shows a cross-sectional structure of a semiconductor device
with use of a lead frame, according to a fourth embodiment of the
present invention. Numeral 11 denotes a semiconductor chip, and 12
a lead frame. The lead frame 12 does not have a die pad portion but
has a chip mount hole. Numeral 13 denotes bonding wires for
electrically connecting electrodes of the semiconductor chip 11 to
the lead frame 12. The semiconductor chip 11 is not fixed at its
upper surface or its lower surface. The chip 11 is mounted in the
chip mount hole in the lead frame 12. The chip 11 is fixed to
support pins of the lead frame 12 on its sides by means of an
adhesive. Numeral 15 denotes a resin package formed by
compression-molding a resin 14 so as to seal the chip 11, bonding
wires 13 and inner lead portions of the lead frame 12.
Since the die pad portion of the lead frame (12a in FIG. 1) is not
provided, a resin-sealed package, which is thinner than the package
of the first embodiment at least by a degree corresponding to the
thickness of the die pad portion of the lead frame, is formed.
The resin-sealed package of the fourth embodiment is manufactured
by manufacturing steps similar to those in the second embodiment.
However, in order to prevent a warp of the package due to
contraction after the molding of thermosetting resin, the thickness
of a resin layer 15a formed on the upper surface of the chip is
made substantially equal to that of a resin layer 15b formed on the
lower surface of the chip. Thus, in the manufacturing steps, the
amount of resin coated on the high-temperature upper mold is set to
be the same as that of resin coated on the high-temperature lower
mold.
FIG. 5 shows a cross-sectional structure of a semiconductor device
with use of a lead frame, according to a fifth embodiment of the
present invention. In this semiconductor device, as compared to the
semiconductor device of the fourth embodiment, the resin layer 15a
formed on the upper surface of the chip 11 is made thicker than the
resin layer 15b formed on the lower surface of the chip 11 in order
to enhance the moisture resistance properties of the package. Thus,
in the manufacturing steps, the amount of resin coated on the
high-temperature upper mold is set to be greater than that of resin
coated on the high-temperature lower mold.
FIG. 6 shows a cross-sectional structure of a semiconductor device
with use of a lead frame, according to a sixth embodiment of the
present invention. In this semiconductor device, as compared to the
semiconductor device of the fourth embodiment, the resin layer 15b
formed on the lower surface of the chip 11 is made thicker than the
resin layer 15a formed on the upper surface of the chip 11 in order
to enhance the anti-package-crack properties of the package when
the package is mounted on a circuit board. Thus, in the
manufacturing steps, the amount of resin coated on the
high-temperature lower mold is set to be greater than that of resin
coated on the high-temperature upper mold.
When the present invention is applied to the semiconductor devices
using the lead frames without die pad portion, as in the
manufacturing steps of the second, fourth, fifth and sixth
embodiments, very thin resin-sealed packages can be formed. In this
case, the amount of resin on the upper and lower surfaces of the
chip can be easily controlled. Thereby, various characteristics can
be improved. For example, if the amount of resin supplied to the
upper mold is set to be the same as that of resin supplied to the
lower mold so that the resin layers formed on the upper and lower
surfaces of the chip may have substantially equal thickness, the
thermal expansion can be well balanced and the package is hardly
warped. In order to enhance the moisture resistance properties of
the chip, the amount of the resin supplied on the upper mold may be
increased and the thickness of the resin layer on the upper surface
of the chip may be increased. In order to enhance the
anti-package-crack properties of the package when the package is
mounted on a circuit board (a package crack occurs when moisture
absorbed in the resin evaporates and expands at an interface of
different materials within the package, resulting in destruction of
the package), the amount of the resin supplied on the lower mold
may be increased and the thickness of the resin layer on the lower
surface of the chip may be increased.
FIG. 7 shows an example of a step of coating a resin on the mold in
the method of manufacturing the semiconductor device according to
the present invention. In this step, a powder resin 24 formed by
powdering a transfer mold resin tablet is sprayed from a nozzle 30
(e.g. one-point nozzle having one open distal end) onto the mold
(the lower mold 10b alone is representatively shown). If a resin
tablet used in the conventional transfer mold method is powdered
and coated, a resin-sealed package having the same properties
(resin physical properties) as the conventional resin-sealed
package can be formed.
FIG. 8 shows another example of a step of coating a resin on the
mold in the method of manufacturing the semiconductor device
according to the present invention. In this step, a liquid resin 34
is sprayed from a nozzle 30 onto the mold (the lower mold 10b alone
is representatively shown). The liquid resin 34 is advantageous in
that it is easily melted. In this case, the liquid resin is jetted
onto the upper mold (not shown) under pressure or coated by a
brush.
FIG. 9 shows an example of the shape of a nozzle used in another
example of a step of coating a resin on the mold in the method of
manufacturing the semiconductor device according to the present
invention. In this example, a resin 14 is simultaneously coated on
the upper and lower molds 10a and 10b from a single nozzle 40.
Thus, the number of coating devices may be one. A distal end
portion of the nozzle 40 is branched into upward and downward
distal end portions. The amount of resin supplied to the upper and
lower molds can be controlled by varying the shape and size of each
distal end portion.
FIG. 10 is a side view showing another example of the shape of a
nozzle used in a step of coating a resin on the mold in the method
of manufacturing the semiconductor device according to the present
invention. In this coating step, two nozzles 51 and 52 are used. A
resin 14 is coated onto the upper and lower molds 10a and 10b from
the two nozzles 51 and 52, respectively. Thus, the resin 14 is
coated onto the upper and lower molds under different conditions.
For example, the amount and type of resin supplied to the upper and
lower molds (e.g. a powder resin onto the upper mold 10a and a
liquid resin onto the lower mold 10b) can be chosen.
FIG. 11 is a side view showing still another example of the shape
of a nozzle used in a step of coating a resin on the mold in the
method of manufacturing the semiconductor device according to the
present invention. In this coating step, a resin is coated from a
multi-point nozzle 50 (having a plurality of opening distal end
portions) onto the upper and lower molds. In this embodiment, the
nozzle has five opening distal end portions. Thereby, the resin can
be uniformly coated in a broad range within the mold. FIG. 11 shows
only opening distal end portions, and does not show the nozzle
body. In this side view, three distal end portions arranged in a
direction perpendicular to the face of FIG. 11 overlap one another
and are viewed as one distal end portion. This nozzle, however, has
five distal end portions, as shown in a plan view. The number of
opening distal end portions is not limited to five.
FIGS. 12A and 12B show other examples of a nozzle used in a step of
coating a resin on the mold in the method of manufacturing the
semiconductor device according to the present invention. In the
coating step shown in FIG. 12A, a one-point nozzle 60 is
reciprocally moved in the direction of a double-headed arrow to
coat the resin 14 on the upper and lower molds. In the coating step
shown in FIG. 12B, a multi-point nozzle 70 is reciprocally moved in
the direction of a double-headed arrow to coat the resin 14 on the
upper and lower molds. Thereby, the resin can be uniformly supplied
in a broad range within the mold.
FIGS. 13 to 16 show other examples of the nozzle used in a step of
coating a resin on the mold in the method of manufacturing the
semiconductor device according to the present invention. In the
coating steps shown in FIGS. 13 and 14, the resin 14 is coated from
a nozzle 71 with a broadened opening end portion or a nozzle 72
with a narrowed opening end portion onto the upper and lower molds.
Thus, the coating of the resin on the molds can be controlled.
In the coating steps shown in FIGS. 15 and 16, the nozzle 71 with
the broadened opening end portion shown in FIG. 13 and the nozzle
72 with the narrowed opening end portion are reciprocally moved in
the direction of a double-headed arrow, thereby coating the resin
14 onto the upper and lower molds. Thereby, the resin can be
uniformly coated on the inside of the mold.
In the steps shown in FIGS. 7 to 16, the resin is supplied from the
respective nozzles onto the upper and lower molds. Thus, the type
of resin supplied onto the upper and lower molds, the thickness of
the resin layer to be formed and the viscosity of the resin are
individually chosen and various packages can be easily
manufactured. For example, a resin with a high moisture resistance
property may be supplied on the upper surface of the chip and a
resin with a low moisture resistance property may be supplied on
the lower surface of the chip in order to prevent a crack in the
package. The resin coating efficiency is enhanced by coating the
resin with the multi-point nozzle or by supplying the resin while
moving the nozzle.
FIGS. 17A and 17B are a plan view and a cross-sectional view
showing a semiconductor device with use of a lead frame, according
to a seventh embodiment of the present invention. In this
semiconductor device, the semiconductor chip 11 is fixed on the
lead frame by bonding wires 13.
As has been described above, according to the present invention,
there is provided a semiconductor device having a very thin, highly
reliable semiconductor package and a method of easily manufacturing
the semiconductor apparatus.
Additional advantages and modifications will readily occur to those
skilled in the art. Therefore, the invention in its broader aspects
is not limited to the specific details, representative devices, and
illustrated examples shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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